Day 1 Tue, February 22, 2022最新文献

Numerical Simulation of the effect of wave characteristics on PTO of Point Absorber Wave Energy Converter 波特性对点吸收波能转换器PTO影响的数值模拟

Day 1 Tue, February 22, 2022 Pub Date : 2022-02-22 DOI: 10.5957/tos-2022-010

A. Hamada, Abigail Rolen, W. McCullough, Mirjam Furth

{"title":"Numerical Simulation of the effect of wave characteristics on PTO of Point Absorber Wave Energy Converter","authors":"A. Hamada, Abigail Rolen, W. McCullough, Mirjam Furth","doi":"10.5957/tos-2022-010","DOIUrl":"https://doi.org/10.5957/tos-2022-010","url":null,"abstract":"The ocean is currently an extremely large and under-developed source of renewable energy. The recent interest in the Blue Economy has led the scientific community to increase investigations in sustainable oceanic energy options, such as PointWave Energy Converters (WEC). These devices harvest the wave energy using the excited oscillatory motion of the buoy, which is connected to a Power Take-Off system (PTO). During the last decades, the development of these devices has been boosted but they are still behind other renewable energy technologies. The Furthlab at Texas A&M University has showed that the spheroid buoy shape with a low length to diameter ratio is a good candidate shape to extract wave energy, by testing different buoy shapes and aspect ratios at a non-linear Stokes-II wave generation. This paper is the next step in our research and numerically investigates the effect of changing the wave characteristics, such as amplitude, frequency, and speed, on the power-generating ability of the spheroid buoy system. Three-dimensional Unsteady Reynolds-Averaged Navier-Stokes (URANS) simulations of the selected buoy were performed in OpenFOAM with the integration of a dynamic mesh module to handle the heave motion of the buoy. In addition, the PTO system was compensated with a forced oscillator mechanism of spring and damper. A comparison between the buoy’s displacement and frequency responses, and power efficiency showed the optimal operating sea state to maximize energy output using the spheroid WEC. The results conclude that the best wave conditions to maximize the power extraction efficiency using a spheroid buoy with a diameter of 1 m and length of 0.5 m are wave length greater than 4 m, wave height less than 0.15 m, and wave speed between 0.07 and 0.12 m/s.","PeriodicalId":108360,"journal":{"name":"Day 1 Tue, February 22, 2022","volume":"229 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117006085","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

A Critical Assessment of Contracting Strategies and Cycle Times of Post-2014 Sanctioned Floating Platforms in the US Gulf of Mexico 2014年后美国墨西哥湾批准的浮式平台合同策略和周期时间的关键评估

Day 1 Tue, February 22, 2022 Pub Date : 2022-02-22 DOI: 10.5957/tos-2022-001

R. D'souza, Shiladitya Basu

{"title":"A Critical Assessment of Contracting Strategies and Cycle Times of Post-2014 Sanctioned Floating Platforms in the US Gulf of Mexico","authors":"R. D'souza, Shiladitya Basu","doi":"10.5957/tos-2022-001","DOIUrl":"https://doi.org/10.5957/tos-2022-001","url":null,"abstract":"Since 1986, about sixty Floating Production Systems (FPSs) have been installed in the US Gulf of Mexico (GoM). They include Spar, Semisubmersible, Tension Leg Platform (TLP) and Floating Production Storage and Offloading (FPSO) platforms. They have been installed in water depths ranging from 500 m to 3,000 m, and production rates ranging from 40,000 boepd to 250,000 boepd. A floating production platform is a major capital investment of a deepwater field development and presents a significant execution challenge. An Operator that opts to install a floating platform for a greenfield development must select a platform type, decide on a contracting strategy and establish credible cycle times for the Appraise, Select, Define and Execute phases of the field development. In their 2021 OTC paper (OTC 31115) the authors undertook a critical assessment of ten major field developments in the GoM, that were sanctioned between 2006 and 2014. They included all four major platform types. A comprehensive database of the field developments including host platform particulars, concept selection, contracting strategies, major engineering, fabrication and installation contractors and cycle times for the four development phases was presented for each project. In the current paper the authors add to the prior body of work, conducting a similar assessment of the seven floating platforms (Appomattox, Argos, Vito, King’s Quay, Anchor, Whale and Shenandoah) that were sanctioned between 2015 and 2021. Taken together, the two papers provide the industry with its most comprehensive accounting of the evolution of GoM floating production platforms, development strategies and cycle times. This information will assist Operators and Development Planners plan and benchmark future GoM deepwater developments with a floating platform. Emerging trends in GoM field developments, following the collapse of oil prices in 2014, and the industry pivot to Energy Transition are also addressed.","PeriodicalId":108360,"journal":{"name":"Day 1 Tue, February 22, 2022","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117011267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Design and analysis of Tidal turbines via a nonlinear optimization technique coupled with a BEM 基于非线性优化技术和边界元法的潮汐涡轮机设计与分析

Day 1 Tue, February 22, 2022 Pub Date : 2022-02-22 DOI: 10.5957/tos-2022-007

Seung-Beom Kim, Thomas S. Wu, S. Kinnas

{"title":"Design and analysis of Tidal turbines via a nonlinear optimization technique coupled with a BEM","authors":"Seung-Beom Kim, Thomas S. Wu, S. Kinnas","doi":"10.5957/tos-2022-007","DOIUrl":"https://doi.org/10.5957/tos-2022-007","url":null,"abstract":"In this paper, a nonlinear optimization method is coupled with a boundary element method (BEM) to design optimum ocean current turbines, and some preliminary results are presented. The optimum turbine geometry is designed to produce the highest power output under several initial constraints. The coordinates of the blade are defined using a B-spline geometry with 4×4 control points being the parameters to be optimized for a given thrust/inflow in the absence of any cavitation. The design process is repeated in an iterative manner by a fully automated interface, which interacts between the hydrodynamic BEM and nonlinear optimization method until the blade geometry becomes fully stabilized, producing maximum power. The present method is first applied to ocean current turbines in open water condition to investigate the influence of design constraints and wake alignment models on the optimal efficiency of the designed blades. full-blown RANS simulations are conducted separately to validate the predicted analysis results using the optimal blade geometry. Comparisons show satisfactory agreement between the results from the present method and those from viscous simulations, and importantly a significant impact of the wake alignment model on the turbine blade design.","PeriodicalId":108360,"journal":{"name":"Day 1 Tue, February 22, 2022","volume":"25 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114026445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Fatigue Life Estimation of Notched Components using Frequency Domain Approach 基于频域法的缺口构件疲劳寿命估计

Day 1 Tue, February 22, 2022 Pub Date : 2022-02-22 DOI: 10.5957/tos-2022-019

D. Sarzosa, Vagner Pascualinotto

引用次数: 0

Prediction of Vessel RAOs: Applications of Deep Learning to Assist in Design 船舶RAOs预测:深度学习在辅助设计中的应用

Day 1 Tue, February 22, 2022 Pub Date : 2022-02-22 DOI: 10.5957/tos-2022-011

James Frizzell, Mirjam Furth

{"title":"Prediction of Vessel RAOs: Applications of Deep Learning to Assist in Design","authors":"James Frizzell, Mirjam Furth","doi":"10.5957/tos-2022-011","DOIUrl":"https://doi.org/10.5957/tos-2022-011","url":null,"abstract":"In an age of high-paced design, a need arises for engineers to quickly estimate the feasibility of their ideas without spending weeks developing a computer model. At the same time, the use of machine learning models, or neural networks, in the maritime industry has grown substantially over the past years. By further extending the use of these predictive models in the design phase, marine engineers and naval architects can expedite their work.\u0000 This paper focuses on the creation of a neural network that can estimate the Response Amplitude Operators (RAOs) of a vessel given its characteristic properties such as length, beam, and draft. A dataset was collected through a parametric design analysis of box barges using ANSYS AQWA, and the RAO was simulated for all 6 degrees of freedom. A critically damped spring equation was generated for each degree. A Keras Neural Network Model was trained on the three parameters and the wave heading angle, with the hidden layers and neuron count being adjusted to optimize the loss and maximize R-squared.\u0000 To validate the results, a series of box barges with dimensions that were not a part of the training dataset were simulated in ANSYS, while the virtual model with identical characteristics was simulated with the Neural Network. The resulting RAOs were compared to validify the accuracy of the Neural Network.\u0000 With this predictive model, engineers can quickly determine a hullform’s RAOs, and compare the response with the common sea states along the intended route. Additionally, the model can assist in design iteration. As the hull shape gradually changes, the new RAOs can be estimated to ensure that the design is progressing in an appropriate direction.","PeriodicalId":108360,"journal":{"name":"Day 1 Tue, February 22, 2022","volume":"116 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134532600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Coupled Control for Motion Compensated Offshore Operations 运动补偿海上作业的耦合控制

Day 1 Tue, February 22, 2022 Pub Date : 2022-02-22 DOI: 10.5957/tos-2022-009

B. Rossin, Atheendra Sreenivasan, B. de Kruif

{"title":"Coupled Control for Motion Compensated Offshore Operations","authors":"B. Rossin, Atheendra Sreenivasan, B. de Kruif","doi":"10.5957/tos-2022-009","DOIUrl":"https://doi.org/10.5957/tos-2022-009","url":null,"abstract":"The use of motion compensated equipment has become more frequent in modern DP operations, especially the ones related to the installation, maintenance and decommissioning of offshore wind turbines. In these operations, while low-frequency motions are compensated by DP systems, wave-frequency motions are compensated by gripper frames, heave compensators, hexapods, gangways and other type of motion compensated equipment. A study was performed to investigate if the coupling of a dynamic positioning system with a motion compensation device could improve the accuracy and efficiency of offshore motion compensated operations. The reference case consisted of the positioning of a payload, hanging on a ship-mounted crane, by means of a single horizontal active tugger line and the ship's DP system. Four controllers – consisting of two levels of awareness and two tuning conditions – were designed and implemented in a numerical model. The four strategies were then evaluated in terms of position offsets and actuator usage under a number of sea-states. Results demonstrated that coupled controllers are able to decrease the position deviations of the motion compensated object and decrease the usage of the motion compensation device. The paper describes the control strategies, numerical models and results of the simulations.","PeriodicalId":108360,"journal":{"name":"Day 1 Tue, February 22, 2022","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125546697","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

High-fidelity turbulence modeling for numerical wave tank applications: Evaluation of the scale-resolving PANS approach 数值波槽应用的高保真湍流建模:尺度分辨PANS方法的评价

Day 1 Tue, February 22, 2022 Pub Date : 2022-02-22 DOI: 10.5957/tos-2022-005

Haneesha Iphineni, B. Windén, S. Girimaji

{"title":"High-fidelity turbulence modeling for numerical wave tank applications: Evaluation of the scale-resolving PANS approach","authors":"Haneesha Iphineni, B. Windén, S. Girimaji","doi":"10.5957/tos-2022-005","DOIUrl":"https://doi.org/10.5957/tos-2022-005","url":null,"abstract":"For analyzing vessel seakeeping, platform wave loads and similar tasks, potential flow-based methods are still the workhorse Numerical Wave Tank (NWT) used by industry. Recently, NWTs have employed more advanced viscous flow simulation methods. These are commonly based on the Reynolds-Averaged Navier-Stokes (RANS) approach. RANS is often preferred by industry due to it’s lower computational cost in relation to better scale resolving methods. The RANS approach however, has limits in NWT applications. Firstly, it is not suited for studying unsteady turbulence phenomena at different scales of wave and fluid motion. Secondly, RANS turbulence models assume that the energy transport in turbulent flows can be described as a dissipative process. In a NWT where large parts of the flow is unsteady, but not dominated by turbulent variations, this could lead to non-physical dissipation of waves.\u0000 Focusing on the second issue, the applicability of the Partially-Averaged Navier-Stokes (PANS) approach in NWTs is investigated in this paper. PANS is a suite of turbulence models of varying modeled to resolved scale ratios ranging from RANS to Direct Numerical Simulation (DNS). PANS modeling allows for more direct control of how energy dissipation is treated. It is hypothesized that this will be beneficial in NWTs by reducing non-physical dissipation of waves.\u0000 Initial results for a regular wave tank are promising. About 40% of the wave amplitude was lost downstream with the RANS approach versus less than 3% with the PANS approach; using the same computational grid and with only a slight increase in the computational effort. Similar results were obtained for a self-contained ”dam break” simulation.","PeriodicalId":108360,"journal":{"name":"Day 1 Tue, February 22, 2022","volume":"113 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122950730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Fatigue Assessment for Steel Lazy-Wave Risers (SLWR) 钢懒波隔水管的疲劳评价

Day 1 Tue, February 22, 2022 Pub Date : 2022-02-22 DOI: 10.5957/tos-2022-020

Song Liu, Xiaochuan Yu, S. Bhat, Keith Wang

{"title":"Fatigue Assessment for Steel Lazy-Wave Risers (SLWR)","authors":"Song Liu, Xiaochuan Yu, S. Bhat, Keith Wang","doi":"10.5957/tos-2022-020","DOIUrl":"https://doi.org/10.5957/tos-2022-020","url":null,"abstract":"Both in-place slug induced riser fatigue and VIV fatigue during pre-laid phases are investigated in this paper for steel lazy wave risers (SLWR) tied back to a deep draft semi-submersible in about 1100m water depth, as part of the full scale engineering study effort for lazy-wave riser design. These results are compared in parallel with fatigue contributions from WLF, VIM and VIV fatigue.\u0000 Dynamic analysis of risers is conducted including the effect of slugging with the vessel in its nominal position to eliminate environmental and vessel motion dynamic effects. Slugs are modelled as variation of mass and inertia, and centrifugal and Coriolis forces are included in the analysis. Rainflow counting method is used to calculate fatigue damage, which is similar to that used for wave loading fatigue analysis. Slug flow conditions are described in terms of lengths of slugs, slug velocity, slug frequency and duration, density of liquid slugs and/or gas bubbles over the field life and including the turn-down and start-up phases and late service life. Analysis results show that the slug fatigue damage contribution for lazy-wave risers can be significantly higher than that for conventional SCRs and it even could play a governing contribution for the buoyancy section.\u0000 In-plane VIV fatigue is investigated for SLWR in wet parked phase with long-term current bins used in the analysis, which is from in-field measurement data. It is found that the riser wet park VIV fatigue analysis can be significant depending on the current profiles, hog bend height and the lay tension.","PeriodicalId":108360,"journal":{"name":"Day 1 Tue, February 22, 2022","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123889952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Modeling Aspects of Running Ductile Fracture Propagation in High Pressure Line Pipes 高压管线运行韧性断裂扩展的建模方法

Day 1 Tue, February 22, 2022 Pub Date : 2022-02-22 DOI: 10.5957/tos-2022-018

M. Paredes

引用次数: 1

Application of a Comprehensive Design Method to Counter-Rotating Propellers 对旋螺旋桨综合设计方法的应用

Day 1 Tue, February 22, 2022 Pub Date : 2022-02-22 DOI: 10.5957/tos-2022-003

K. Cha, S. Kinnas

引用次数: 1